Multi-layer structure for transporting or storing hydrogen

Abstract

Multilayer structure for transporting, distributing and storing hydrogen, which comprises from the inside out at least one sealing layer (1) and at least one composite reinforcing layer (2), the innermost composite reinforcing layer being wound around the outermost adjacent sealing layer (1), the sealing layer being composed of a composition which mainly comprises: at least one semi-crystalline long-chain polyamide thermoplastic polymer P1i (i = 1 to n, n being the number of sealing layers), having a Tf greater than 160 °C as measured according to ISO 11357-3:2013, excluding polyether block amide (PEBA); an impact modifier up to 50% by weight relative to the total weight of the composition and a plasticizer up to 1.5% by weight relative to the total weight of the composition, the composition being free of nucleating agents, at least one polyamide thermoplastic polymer of each sealing layer being able to be the same or different, and at least one of the composite reinforcing layers being composed of a fibrous material in the form of continuous fibres impregnated with a composition which mainly comprises at least one polymer P2j (j = 1 to m, m being the number of reinforcing layers), in particular an epoxy resin or an epoxy-based resin, and the structure being free of an outermost layer adjacent to the outermost polyamide polymer composite reinforcing layer.

Description

Technical Field

[0001] This patent application relates to the transport (conveyance), distribution, or storage of hydrogen, particularly a multi-layer composite structure for the distribution or storage of hydrogen, and a method for manufacturing the same. Background Art

[0002] Hydrogen tanks are currently attracting a lot of attention from many manufacturers, especially those in the automotive industry. One of the sought-after goals is to come up with vehicles that cause less pollution. Thus, electric or hybrid vehicles including batteries are intended to gradually replace internal combustion engine vehicles such as gasoline or diesel vehicles. It has been proven that batteries are relatively complex vehicle components. Depending on the placement (position) of the battery in the vehicle, it may be necessary to protect it from impacts and from the external environment that can have extreme temperatures and variable humidity. It is also necessary to avoid any risk of fire.

[0003] In addition, the following is important: its operating temperature does not exceed 55 °C so as not to damage the unit cells of the battery and to maintain its lifespan. On the contrary, for example in winter, it may be necessary to increase the battery temperature to optimize its operation.

[0004] Moreover, electric vehicles still suffer from several problems today, namely the battery range, the use of rare earth metals in these batteries, the resources for them are not infinite, the recharging time which is much longer than the time length for filling a tank, and the problem of electricity production in various countries in order to be able to recharge the battery.

[0005] Therefore, hydrogen is an alternative to electric batteries because hydrogen can be converted into electricity through a fuel cell and thus drive an electric vehicle.

[0006] Hydrogen tanks often consist of a metal lining (or sealing layer) that must prevent hydrogen from leaking out. One of the types of tanks in prospect, called type IV, is based on a thermoplastic lining around which a composite is wound.

[0007] Their basic principle is to separate the two basic functions of sealing and mechanical strength and manage them independently of each other. In this type of tank, a lining (or sealing sheath) made of a thermoplastic resin is combined with a reinforcing structure composed of fibers (glass, aramid, carbon), also called a reinforcing sheath or layer, which enables operation at much higher pressures while reducing weight and avoiding the risk of explosive rupture in case of a severe external attack.

[0008] The lining must have some basic properties:

[0009] The possibility of being deformed (formed) by extrusion blow molding, rotational molding (rotational moulding), injection molding or extrusion;

[0010] Low hydrogen permeability. In fact, the permeability of the liner is a key factor in limiting hydrogen loss from the tank;

[0011] Good mechanical properties (fatigue) at low temperatures (-40 to -70 °C);

[0012] Heat resistance at 120 °C.

[0013] In fact, the following is necessary: to increase the filling speed of the hydrogen tank, which should roughly equal the filling speed of the fuel tank for an internal combustion engine (about 3 to 5 minutes), but this increase in speed results in more significant heating of the tank, which then reaches a temperature of about 100 °C.

[0014] The evaluation of the performance and safety of hydrogen tanks can be determined in reference European laboratories (GasTeF: Hydrogen Tank Test Facility), as described by Galassi et al. (World hydrogen energy conference 2012, Onboard compressed hydrogen storage: fast filing experiments and simulations, Energy Procedia 29, (2012) 192 - 200).

[0015] The first generation of type-IV tanks uses a liner based on high-density polyethylene (HDPE).

[0016] However, HDPE has the following disadvantages: it has too low a melting point and high hydrogen permeability, which poses problems for new requirements in heat resistance and does not make it possible to increase the filling speed of the tank.

[0017] Liners based on polyamide PA6 have been developed for many years.

[0018] However, PA6 has the following disadvantage: it has low cold resistance.

[0019] Patent application EP3112421 describes a polyamide resin composition for molded articles intended for high-pressure hydrogen, which composition comprises:

[0020] Polyamide 6 resin (A); and a polyamide resin (B) having a melting point, such as measured by DSC, not greater than the melting point of polyamide 6 resin (A) + 20 °C and a crystallization temperature on cooling, such as measured by DSC, higher than that of polyamide 6 resin (A).

[0021] French application FR2923575 describes a tank for storing fluids under high pressure, which includes metal end members at each of its ends along its axis, a lining surrounding said end members, and a structural layer made of fibers impregnated with a thermosetting resin surrounding said lining.

[0022] Application EP3222668 describes a polyamide resin composition for a molded article intended for high-pressure hydrogen, the composition comprising a polyamide resin (A) including units derived from hexamethylenediamine and units derived from an aliphatic dicarboxylic acid having 8 to 12 carbon atoms and an ethylene / α-olefin copolymer (B) modified with one of an unsaturated carboxylic acid and / or its derivatives.

[0023] Application US2014 / 008373 describes a lightweight storage cylinder for high-pressure compressed gas, the cylinder having a lining surrounded by a constraining layer, the lining comprising:

[0024] a first impact-modified polyamide (PA) inner layer in contact with the gas,

[0025] a thermoplastic outer layer in contact with the constraining layer; and

[0026] an adhesive bonding layer between the first impact-modified PA inner layer and the thermoplastic outer layer.

[0027] WO18155491 describes a hydrogen transport assembly having a three-layer structure, the inner layer of which is a composition consisting of: PA11, 15 to 50% impact modifier, and 1 to 3% plasticizer, or without (excluding) plasticizer, which has hydrogen barrier properties, good flexibility, and durability at low temperatures. However, this structure is suitable for use in pipelines for transporting hydrogen but not for storing hydrogen.

[0028] Thus, there is still a need: on the one hand, to optimize the matrix of the composite to optimize its mechanical strength at high temperatures, and on the other hand, to optimize the material constituting the sealing sheath to optimize its operating temperature. Thus, any optional modification of the composition of the material constituting the sealing lining to be implemented must not result in a significant increase in the manufacturing temperature (extrusion blow molding, injection molding, rotational molding, etc.) of the lining compared to what is practiced today.

[0029] These problems are solved by providing the multi-layer structure of the present invention intended for transporting, distributing, or storing hydrogen.

[0030] Throughout the specification, the terms "lining" and "sealing sheath" have the same meaning.

[0031] The present invention thus relates to a multi-layer structure intended for transporting, distributing, or storing hydrogen, which includes at least one sealing layer (1) and at least one composite reinforcing layer (2) from the inside to the outside,

[0032] The innermost composite reinforcing layer is wound around the outermost adjacent sealing layer (1),

[0033] The sealing layer(s) consists of a composition mainly comprising:

[0034] At least one semi-crystalline thermoplastic polymer P1i where i = 1 to n, n being the number of sealing layers, having a Tm greater than 160 °C, particularly greater than 170 °C as measured according to ISO11357-3:2013, excluding polyether block amide (PEBA),

[0035] An impact modifier up to (at most) 50 wt% relative to the total weight of the composition, particularly up to less than 15 wt% and especially up to 12 wt% of the impact modifier,

[0036] A plasticizer up to 1.5 wt% relative to the total weight of the composition,

[0037] The composition has no nucleating agent,

[0038] The at least one polyamide thermoplastic polymer of each sealing layer can be the same or different,

[0039] And at least one of the composite reinforcing layers consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one polymer P2j, where j = 1 to m, m being the number of reinforcing layers, particularly an epoxy resin or epoxy-based resin,

[0040] The structure has no outermost layer and is adjacent to the outermost polyamide polymer composite reinforcing layer.

[0041] Thus, the inventors unexpectedly found that using long-chain semi-crystalline polyamide thermoplastic polymers with a limited proportion of impact modifier and plasticizer for the sealing layer and a different polymer, particularly an epoxy resin or epoxy-based resin, for the matrix of the composite (the composite being wound around the sealing layer) enables the obtaining of a structure suitable for transporting, dispensing, or storing hydrogen, and in particular an increase in the maximum use temperature, which can be extended up to 120 °C, thereby enabling an increase in the filling rate of the tank.

[0042] By "multi-layer structure", it is to be understood a tank comprising or consisting of several layers, namely several sealing layers and several reinforcing layers, or one sealing layer and several reinforcing layers, or several sealing layers and one reinforcing layer, or one sealing layer and one reinforcing layer.

[0043] The multi-layer structure is thus understood to exclude pipes or tubes.

[0044] Polyether block amide (PEBA) is a copolymer having amide units (Ba1) and polyether units (Ba2), and the amide units (Ba1) correspond to aliphatic repeating units selected from the following: units obtained from at least one amino acid or units obtained from at least one lactam, or units obtained from the polycondensation of the following X.Y:

[0045] - at least one diamine, which is preferably selected from linear or branched aliphatic diamines or mixtures thereof, and

[0046] - at least one dicarboxylic acid, which is preferably selected from:

[0047] linear or branched aliphatic dicarboxylic acids, or mixtures thereof,

[0048] the diamine and the dicarboxylic acid contain 4 to 36 carbon atoms, advantageously 6 to 18 carbon atoms;

[0049] The polyether unit (Ba2) is particularly obtained from at least one polyalkylene ether polyol, especially polyalkylene ether diol.

[0050] Nucleating agents are known to those skilled in the art and the term refers to substances that, when introduced into a polymer, form nuclei for crystal growth in the molten polymer.

[0051] They can be selected, for example, from microtalc, carbon black, silica, titanium dioxide, and nanoclay.

[0052] In one embodiment, PA6 and PA610 are excluded from the composition.

[0053] The expression "the structure has no outermost layer and is adjacent to the outermost polyamide polymer composite reinforcement layer" means that the structure has no layer of polyamide polymer above the outermost composite reinforcement layer.

[0054] In one embodiment, the multi-layer structure consists of the following two layers: a sealing layer and a reinforcement layer.

[0055] One or more sealing layers are the innermost layers compared to the outermost composite reinforcement layer.

[0056] The tank can be a tank for the mobile storage of hydrogen on a truck for transporting hydrogen, on a car for transporting hydrogen and supplying hydrogen to a fuel cell, for example, on a train for supplying hydrogen or on a drone for supplying hydrogen, but it can also be a tank for the static storage of hydrogen in a station for distributing hydrogen to vehicles (transportation means).

[0057] Advantageously, the sealing layer (1) is impermeable to hydrogen at 23 °C, i.e., has a hydrogen permeability of less than 500 cc.mm / m 2 .24h.atm at 23 °C at 0% relative humidity (RH).

[0058] In one embodiment, the one or more sealing layers consist of a composition mainly comprising:

[0059] at least one semi-crystalline thermoplastic polymer P1 where i = 1 to n and n is the number of sealing layers, having a Tm greater than 160 °C, particularly greater than 170 °C as measured according to ISO11357-3:2013, excluding polyether block amide (PEBA), and excluding PA11.

[0060] The composite reinforcement layer(s) is / are wound around the sealing layer by means of a tape (or strip or roving) of polymer-impregnated fibers, for example, deposited by filament winding.

[0061] When there are several layers, the polymers are different.

[0062] When the polymers of the reinforcement layers are the same, several layers may be present, but advantageously there is a single reinforcement layer, which then has at least one complete winding around the sealing layer.

[0063] This fully automated process, well-known to those skilled in the art, enables the winding angle to be selected layer by layer, which will give the final structure its ability to withstand internal pressure loads.

[0064] When there are several sealing layers, only the innermost one is in direct contact with hydrogen.

[0065] When there is only one sealing layer and one composite reinforcement layer, resulting in a two-layer multi-layer structure, then these two layers can adhere to each other directly in contact, especially due to the composite reinforcement layer being wound over the sealing layer.

[0066] When there are several sealing layers and / or several composite reinforcement layers, then the outermost layer of the sealing layers and thus the layer opposite the layer in contact with hydrogen may or may not adhere to the innermost composite reinforcement layer.

[0067] Other composite reinforcement layers may also adhere to each other or may not adhere to each other.

[0068] Other sealing layers may also adhere to each other or may not adhere to each other.

[0069] Advantageously, there is only one sealing layer and one reinforcement layer, and they do not adhere to each other.

[0070] Advantageously, there is only one sealing layer and one reinforcing layer, which do not adhere to each other, and the reinforcing layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one polymer P2j, in particular an epoxy resin or an epoxy-based resin.

[0071] In one embodiment, there is only one sealing layer and one reinforcing layer, which do not adhere to each other, and the reinforcing layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising a polymer P2j, where the polymer P2j is an epoxy resin or an epoxy-based resin.

[0072] The expression "epoxy-based" throughout the specification means that the epoxy accounts for at least 50% by weight of the matrix.

[0073] Regarding the sealing layer(s) and the thermoplastic polymer P1i

[0074] One or more sealing layers may be present.

[0075] Each of the layers consists of a composition mainly comprising at least one thermoplastic polymer P1i, where i corresponds to the number of layers present. i is from 1 to 10, in particular from 1 to 5, especially from 1 to 3, and preferably i = 1.

[0076] The term "mainly" means that the at least one polymer is present in an amount of more than 50% by weight relative to the total weight of the composition.

[0077] Advantageously, the at least one main polymer is present in an amount of more than 60% by weight, in particular more than 70% by weight, especially more than 80% by weight, and more particularly greater than or equal to 90% by weight relative to the total weight of the composition.

[0078] The composition may further comprise up to 50% by weight, relative to the total weight of the composition, of an impact modifier and / or a plasticizer and / or an additive.

[0079] The additives may be selected from another polymer, an antioxidant, a heat stabilizer, a UV absorber, a light stabilizer, a lubricant, an inorganic filler, a flame retardant, a dye, carbon black, and a carbonaceous nanofiller, except for a nucleating agent; in particular, the additives are selected from an antioxidant, a heat stabilizer, a UV absorber, a light stabilizer, a lubricant, an inorganic filler, a flame retardant, a dye, carbon black, and a carbonaceous nanofiller, except for a nucleating agent.

[0080] The other polymer may be a semi-crystalline thermoplastic polymer or a different polymer, and in particular EVOH (ethylene vinyl alcohol).

[0081] Advantageously, the composition mainly comprises the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, in particular 0 to less than 15% of an impact modifier, particularly 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer and 0 to 5% by weight of additives, the sum of the components of the composition being equal to 100%.

[0082] Advantageously, the composition mainly consists of: the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, in particular 0 to less than 15% of an impact modifier, particularly 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer and 0 to 5% by weight of additives, the sum of the components of the composition being equal to 100%.

[0083] The at least one main polymer in each layer may be the same or different.

[0084] In one embodiment, a single main polymer is present in at least the following sealing layer: the sealing layer does not adhere to the composite reinforcing layer.

[0085] In one embodiment, the composition comprises 0.1 to 50% by weight, in particular 0.1 to less than 15% by weight, particularly 0.1 to 12% by weight of an impact modifier, relative to the total weight of the composition.

[0086] In one embodiment, the composition has no plasticizer.

[0087] In another embodiment, the composition comprises 0.1 to 50% by weight, in particular 0.1 to less than 15% by weight, particularly 0.1 to 12% by weight of an impact modifier, and the composition has no plasticizer, relative to the total weight of the composition.

[0088] In yet another embodiment, the composition comprises 0.1 to 50% by weight, in particular 0.1 to less than 15% by weight, particularly 0.1 to 12% by weight of an impact modifier and 0.1 to 1.5% by weight of a plasticizer, relative to the total weight of the composition.

[0089] In another embodiment, the composition has no impact modifier.

[0090] Advantageously, the composition comprises 0.1 to 1.5% by weight of a plasticizer, relative to the total weight of the composition, and the composition has no impact modifier.

[0091] In another embodiment, the composition has no impact modifier and no plasticizer.

[0092] In the previous embodiment, the composition mainly comprises the thermoplastic polymer P1i and from 0 to 5% by weight of additives, in particular from 0.1 to 5% of additives, the sum of the components of the composition being equal to 100%.

[0093] In this case, the main thermoplastic polymer P1i is mixed with another polyamide.

[0094] Advantageously, the composition mainly consists of: the thermoplastic polymer P1i and from 0 to 5% by weight of additives, in particular from 0.1 to 5% of additives, the sum of the components of the composition being equal to 100%.

[0095] Advantageously, the composition mainly consists of: the thermoplastic polymer P1i, from 0 to 5% by weight of additives, in particular from 0.1 to 5% of additives, the sum of the components of the composition being equal to 100%.

[0096] In this case, the main thermoplastic polymer P1i is mixed with another polyamide.

[0097] Advantageously, the composition consists of: the thermoplastic polymer P1i and from 0 to 5% of additives, in particular from 0.1 to 5% of additives, the sum of the components of the composition being equal to 100%.

[0098] Thermoplastic polymer P1i

[0099] A thermoplastic polymer or a semi-crystalline thermoplastic polymer refers to a material which is usually solid at ambient temperature and which softens during the rise in temperature, in particular after exceeding its glass transition temperature (Tg), and exhibits a sharp transition when exceeding its so-called melting point (Tm), and which becomes solid again when the temperature drops below its crystallization temperature.

[0100] Tg, Tc and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013 respectively.

[0101] The number average molecular weight Mn of the semi-crystalline polyamide thermoplastic polymer is preferably in the range from 10,000 to 85,000, in particular from 10,000 to 60,000, preferably from 10,000 to 50,000, even more preferably from 12,000 to 50,000. These Mn values can correspond to an intrinsic viscosity of greater than or equal to 0.8, as determined in m-cresol in accordance with standard ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20 °C).

[0102] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011, “Plastiques – Matériaux polyamides (PA) pour moulage et extrusion – Partie 1: Désignation,” particularly on page 3 (Tables 1 and 2) and is well known to those skilled in the art.

[0103] The polyamide can be a homopolyamide, a copolyamide, or a mixture thereof.

[0104] In one embodiment, the thermoplastic polymer is a long-chain aliphatic polyamide, i.e., a polyamide having an average number of carbon atoms per nitrogen atom greater than or equal to 8.5, preferably greater than 9, particularly greater than 10.

[0105] In particular, the long-chain aliphatic polyamides are selected from:

[0106] Polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or a mixture or copolyamide thereof, particularly PA11 and PA12.

[0107] More particularly, polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or a mixture or copolyamide thereof, particularly PA11 and PA12.

[0108] In one embodiment, the long-chain aliphatic polyamides are selected from:

[0109] Polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or a mixture or copolyamide thereof, particularly PA12.

[0110] In another embodiment, the long-chain aliphatic polyamides are selected from:

[0111] Polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or a mixture or copolyamide thereof, particularly PA12.

[0112] Advantageously, the semi-crystalline thermoplastic polymer is a long-chain semi-aromatic semi-crystalline polyamide, i.e., a polyamide having an average number of carbon atoms per nitrogen atom greater than 8.5, preferably greater than 9, particularly greater than 10 and a melting point of from 240 °C to less than 280 °C.

[0113] In particular, the long-chain semi-aromatic semi-crystalline polyamide is selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, PMDT / 10T and BACT / 10T.

[0114] Advantageously, each sealing layer consists of a composition comprising the same type of polyamide.

[0115] If welding is necessary, there are various methods for making weldable elements made of polyamide thermoplastic polymers. Thus, contact or non-contact heating blades, ultrasound, infrared, vibration, rotating one element to be welded against another or even laser welding can be used.

[0116] Regarding the impact modifier

[0117] The impact modifier can be any impact modifier as long as it is a polymer having a modulus lower than that of the resin and having good adhesion to the matrix to dissipate the cracking energy.

[0118] The impact modifier advantageously consists of a polymer, in particular a polyolefin, having a flexural modulus of less than 100 MPa measured according to standard ISO 178 and a Tg of less than 0 °C (measured at the inflection point of the DSC thermogram according to standard 11357-2).

[0119] In one embodiment, PEBA is excluded from the definition of the impact modifier.

[0120] The polyolefin of the impact modifier can be functionalized or non-functionalized or a mixture of at least one functionalized polyolefin and / or at least one non-functionalized polyolefin. For the sake of simplicity, the polyolefin is denoted by (B) and the functionalized polyolefin (B1) and the non-functionalized polyolefin (B2) are described below.

[0121] The non-functionalized polyolefin (B2) is classically a homopolymer or copolymer of an α-olefin or a diene such as, for example, ethylene, propylene, 1-butene, 1-octene, butadiene. As examples, mention may be made of:

[0122] - Homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene.

[0123] - Homopolymers or copolymers of propylene.

[0124] - Ethylene / α-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene rubber) and ethylene / propylene / diene (ethylene-propylene-diene rubber) (EPDM).

[0125] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0126] - Copolymers of ethylene with at least one product selected from: salts or esters of unsaturated carboxylic acids such as (meth)acrylic acid alkyl esters (e.g., methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), where the proportion of comonomer can reach 40% by weight.

[0127] The functionalized polyolefin (B1) can be a polymer of α-olefins having reactive units (functional groups); such reactive units are acid, anhydride, or epoxy functional groups. As an example, mention may be made of the foregoing polyolefin (B2) grafted, copolymerized, or terpolymerized with an unsaturated epoxide such as glycidyl (meth)acrylate, or with a carboxylic acid or the corresponding salt or ester such as (meth)acrylic acid (which may be fully or partially neutralized with a metal such as Zn, etc.), or even with a carboxylic anhydride such as maleic anhydride. The functionalized polyolefin is, for example, a PE / EPR mixture, the ratio of which by weight can vary within a wide range, for example between 40 / 60 and 90 / 10, and the mixture is co-grafted with an anhydride, especially maleic anhydride, according to a grafting rate of, for example, 0.01 to 5% by weight.

[0128] The functionalized polyolefin (B1) can be selected from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, where the grafting rate is, for example, 0.01 to 5% by weight:

[0129] - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing, for example, 35 to 80% by weight of ethylene;

[0130] - Ethylene / α-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene rubber), and ethylene / propylene / diene (EPDM).

[0131] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0132] - Copolymers of ethylene and vinyl acetate (EVA) containing up to 40% by weight of vinyl acetate;

[0133] - Copolymers of ethylene and (meth)acrylic acid alkyl esters containing up to 40% by weight of (meth)acrylic acid alkyl esters;

[0134] - Copolymers of ethylene with vinyl acetate (EVA) and (meth)acrylic acid alkyl esters containing up to 40% by weight of comonomers.

[0135] The functionalized polyolefin (B1) may also be selected from ethylene / propylene copolymers in which propylene grafted mainly with maleic anhydride is condensed with monoamine polyamides (or polyamide oligomers) (products described in EP-A-0,342,066).

[0136] The functionalized polyolefin (B1) may also be a copolymer or terpolymer of at least the following units: (1) ethylene, (2) (meth)acrylic acid alkyl esters or vinyl esters of saturated carboxylic acids, and (3) anhydrides such as maleic anhydride or (meth)acrylic acid or epoxies such as glycidyl (meth)acrylate.

[0137] As an example of the latter type of functionalized polyolefin, the following copolymers may be mentioned: in which ethylene preferably accounts for at least 60% by weight of the copolymer and in which the terpolymer monomer (functional group) accounts for, for example, 0.1 to 10% by weight of the copolymer:

[0138] - Ethylene / (meth)acrylic acid alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer;

[0139] - Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymer;

[0140] - Ethylene / vinyl acetate or (meth)acrylic acid alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer.

[0141] In the foregoing copolymers, (meth)acrylic acid may be salified with Zn or Li.

[0142] The term “(meth)acrylic acid alkyl ester” in (B1) or (B2) means C1-C8 alkyl esters of methacrylic acid and C1-C8 alkyl esters of acrylic acid, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0143] Moreover, the aforementioned polyolefin (B1) may also be crosslinked by any suitable method or reagent (diepoxies, diacids, peroxides, etc.); the term functionalized polyolefin also includes mixtures of the aforementioned polyolefins with bifunctional reagents such as diacids, dianhydrides, diepoxies, etc. that can react with these, or mixtures of at least two functionalized polyolefins that can react together.

[0144] The aforementioned copolymers (B1) and (B2) may be copolymerized in a statistical or sequential manner and have a linear or branched structure.

[0145] The molecular weight, melt flow index (MFI), and density of these polyolefins can also be varied within a wide range, and those skilled in the art will be aware of this. MFI, an abbreviation for melt flow index, is a measure of the fluidity in the molten state. It is measured according to standard ASTM 1238.

[0146] Advantageously, the non-functionalized polyolefin (B2) is selected from homopolymers or copolymers of polypropylene and any ethylene homopolymer or copolymer of ethylene with higher α-olefin comonomers such as butene, hexene, octene, or 4-methyl-1-pentene. Mention may be made, for example, of PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, very-low-density PE. These polyethylene are known to those skilled in the art to be manufactured according to the "free radical" method, according to the "Ziegler" catalytic method, or more recently the "metallocene" catalysis.

[0147] Advantageously, the functionalized polyolefin (B1) is selected from any polymer comprising α-olefin units and units with polar reactive functional groups such as epoxy, carboxylic acid, or carboxylic anhydride functional groups. As an example of such a polymer, mention may be made of terpolymers of ethylene, alkyl acrylate, and maleic anhydride or glycidyl methacrylate, for example from the applicant or polyolefins grafted with maleic anhydride, for example from the applicant and terpolymers of ethylene, alkyl acrylate, and (meth)acrylic acid. Mention may also be made of homopolymers of polypropylene or copolymers of polypropylene grafted with carboxylic anhydride and then condensed with polyamide or monoamine polyamide oligomers.

[0148] Advantageously, the composition(s) constituting the seal layer(s) does not have polyether block amide (PEBA). In this embodiment, therefore, PEBA is excluded from the impact modifier.

[0149] Advantageously, the transparent composition does not have core-shell particles or core-shell polymers.

[0150] Core-shell particles must be understood as particles in which the first layer forms the core and the second or all subsequent layers form the corresponding shell.

[0151] Core-shell particles can be obtained by a method having several steps including at least two steps. Such a method is described, for example, in the documents US2009 / 0149600 or EP0,722,961.

[0152] Regarding plasticizers:

[0153] The plasticizer can be a plasticizer commonly used in compositions based on polyamide(s).

[0154] Advantageously, a plasticizer is used which has good thermal stability such that it does not form fumes during the steps of mixing the different polymers and deforming the resulting composition.

[0155] In particular, the plasticizer is selected from:

[0156] benzenesulfonamide derivatives such as the ortho- and para-isomers of n-butylbenzenesulfonamide (BBSA), ethyltoluenesulfonamide (ETSA), N-cyclohexyltoluenesulfonamide and N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA),

[0157] esters of hydroxybenzoic acid such as 2-ethylhexyl p-hydroxybenzoate (EHPB) and 2-decylhexyl p-hydroxybenzoate (HDPB),

[0158] esters or ethers of tetrahydrofurfuryl alcohol such as oligoethyleneoxy tetrahydrofurfuryl alcohol, and

[0159] esters of citric acid or hydroxypropanedioic acid such as oligoethyleneoxy propanedioate.

[0160] A preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0161] Another more particularly preferred plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). In fact, the latter has the advantage of preventing the formation of deposits ("die drool") at the extruder screw and / or die during the deformation step by extrusion.

[0162] Of course, mixtures of plasticizers can be used.

[0163] Regarding the composite reinforcement layer and the polymer P2j

[0164] The polymer P2j can be a thermoplastic polymer or a thermosetting polymer.

[0165] One or more composite reinforcement layers can be present.

[0166] Each of said layers consists of a fibrous material in the form of continuous fibers impregnated with a composition which mainly comprises at least one thermoplastic polymer P2j, where j corresponds to the number of layers present.

[0167] j includes 1 to 10, particularly 1 to 5, especially 1 to 3, and preferably j = 1.

[0168] The term "mainly" means that the at least one polymer is present in an amount of more than 50% by weight relative to the total weight of the composition and the matrix of the composite.

[0169] Advantageously, relative to the total weight of the composition, the at least one major polymer is present in an amount of more than 60% by weight, particularly more than 70% by weight, especially more than 80% by weight, and more particularly greater than or equal to 90% by weight.

[0170] The composition may further comprise an impact modifier and / or additives.

[0171] The additives may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, plasticizers, and dyes, excluding nucleating agents.

[0172] Advantageously, the composition consists essentially of: the thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, particularly 0 to 12% by weight of an impact modifier, 0 to 5% by weight of additives, with the sum of the components of the composition being equal to 100% by weight.

[0173] The at least one major polymer in each layer may be the same or different.

[0174] In one embodiment, a single major polymer is present at least in the composite reinforcing layer and does not adhere to the sealing layer.

[0175] In one embodiment, each reinforcing layer comprises the same type of polymer, particularly an epoxy resin or an epoxy-based resin.

[0176] Polymer P2j

[0177] Thermoplastic polymer P2j

[0178] A thermoplastic material, or a thermoplastic polymer, refers to a material that is usually solid at ambient temperature, which may be semi-crystalline or amorphous, particularly semi-crystalline, and which, when it is amorphous, softens during a temperature increase, particularly after exceeding its glass transition temperature (Tg), and flows at a higher temperature, or which, when it is semi-crystalline, may exhibit a sharp transition when exceeding its so-called melting point (Tm), and which becomes solid again when the temperature is lowered below its crystallization temperature Tc (for semi-crystalline) and below its glass transition temperature (for amorphous).

[0179] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0180] The number-average molecular weight Mn of the thermoplastic polymer is preferably in the range of 10,000 to 40,000, preferably 10,000 to 30,000. These Mn values can correspond to an intrinsic viscosity greater than or equal to 0.8, as determined in m-cresol according to standard ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20 °C).

[0181] Examples of suitable semi-crystalline thermoplastic polymers in the present invention include:

[0182] Polyamides, which particularly include aromatic and / or alicyclic structures, and the polyamides include copolymers, such as polyamide-polyether copolymers,

[0183] Polyesters,

[0184] Polyaryletherketones (PAEK),

[0185] Polyetheretherketones (PEEK),

[0186] Polyetherketoneketones (PEKK),

[0187] Polyetherketoneetherketoneketones (PEKEKK),

[0188] Polyimides, particularly polyetherimides (PEI) or polyamide-imides,

[0189] Polysulfones (PSU), particularly polyarylsulfones such as polyphenylsulfone (PPSU),

[0190] Polyethersulfones (PES).

[0191] Semi-crystalline polymers, and particularly polyamides and their semi-crystalline copolymers are more particularly preferred.

[0192] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques – Matériaux polyamides (PA) pour moulage et extrusion – Partie 1: Désignation”, particularly on page 3 (Tables 1 and 2) and is well known to those skilled in the art.

[0193] The polyamide can be a homopolyamide or a copolyamide or a mixture thereof.

[0194] Advantageously, the semi-crystalline polyamide is a semi-aromatic polyamide, in particular a semi-aromatic polyamide of the formula X / YAr as described in EP1505099, particularly a semi-aromatic polyamide of the formula A / XT, where A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Ca diamine).(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, the unit (Ca diamine) being selected from linear or branched aliphatic diamines, cycloaliphatic diamines, and alkylaromatic diamines and the unit (Cb diacid) being selected from linear or branched aliphatic diacids, cycloaliphatic diacids, and aromatic diacids;

[0195] X.T represents a unit obtained by polycondensation of a Cx diamine and terephthalic acid, where x represents the number of carbon atoms of the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, in particular polyamides having the formula A / 5T, A / 6T, A / 9T, A / 10T, or A / 11T, A being as defined above, particularly polyamides selected from among: PA MPMDT / 6T, PA11 / 10T, PA5T / 10T, PA11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PA 11 / 5T / 10T.

[0196] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine and BAC corresponds to bis(aminomethyl)cyclohexane. The semi-aromatic polyamides defined above particularly have a Tg greater than or equal to 80 °C.

[0197] Thermosetting polymer P2j

[0198] The thermosetting polymer is selected from epoxy resins or epoxy-based resins, polyesters, vinyl esters, and polyurethanes, or mixtures thereof, particularly epoxy resins or epoxy-based resins.

[0199] Advantageously, each composite reinforcing layer consists of a composition comprising the same type of polymer, particularly an epoxy resin or an epoxy-based resin.

[0200] The composition comprising the polymer P2j may be transparent to radiation suitable for welding.

[0201] In another embodiment, the composite reinforcing layer is wound around the sealing layer without any subsequent welding.

[0202] Regarding the structure

[0203] Said multi-layer structure thus comprises a sealing layer and at least one composite reinforcement layer wound around the sealing layer and which may or may not adhere to each other.

[0204] Advantageously, the sealing layer and the reinforcement layer do not adhere to each other and are composed of compositions respectively comprising different polymers.

[0205] However, the different polymers may be of the same type.

[0206] Thus, if one of the two welded composite reinforcement and sealing layers is made of a composition comprising an aliphatic polyamide, the other layer is composed of a composition comprising a polyamide which is not aliphatic and which is, for example, a semi-aromatic polyamide to have a high Tg polymer as the matrix of the composite reinforcement.

[0207] The multi-layer structure may comprise up to 10 composite reinforcement layers and up to 10 sealing layers of different nature.

[0208] Advantageously, there is no binder or adhesive layer between the sealing layers, or between the composite reinforcement layers, or even between the outermost sealing layer and the innermost composite reinforcement layer of the structure.

[0209] Obviously, the multi-layer structure does not have to be symmetrical and it may thus comprise more sealing layers than composite layers or vice versa, but there may be no alternation of layers and reinforcement layers.

[0210] Advantageously, the multi-layer structure comprises one, two, three, four, five, six, seven, eight, nine or ten sealing layers and one, two, three, four, five, six, seven, eight, nine or ten composite reinforcement layers.

[0211] Advantageously, the multi-layer structure comprises one, two, three, four or five sealing layers and one, two, three, four or five composite reinforcement layers.

[0212] Advantageously, the multi-layer structure comprises one, two or three sealing layers and one, two or three composite reinforcement layers.

[0213] Advantageously, they are composed of compositions respectively comprising different polymers.

[0214] Advantageously, they are composed of compositions respectively comprising a polyamide corresponding to polyamide PA1i and an epoxy resin or epoxy-based resin P2j.

[0215] In one embodiment, the multi-layer structure includes a sealing layer and a plurality of reinforcing layers, with adjacent reinforcing layers wound around the sealing layer and other reinforcing layers wound around directly adjacent reinforcing layers.

[0216] In another embodiment, the multi-layer structure includes a single reinforcing layer and a plurality of sealing layers, with the reinforcing layer wound around the adjacent sealing layers.

[0217] In an advantageous embodiment, the multi-layer structure includes a single sealing layer and a single composite reinforcing layer, with the reinforcing layer wound around the sealing layer.

[0218] Therefore, all combinations of these two layers are within the scope of the present invention, provided that at least the innermost composite reinforcing layer is wound around the outermost adjacent sealing layer, and the other layers may or may not adhere to each other.

[0219] Advantageously, in the multi-layer structure, each sealing layer is composed of a composition including the same type of polymer P1i, particularly a polyamide.

[0220] The expression "the same type of polymer" means that, for example, the polyamide may be the same or different polyamides depending on the layer.

[0221] Advantageously, the polymer P1i is a polyamide and the polymer P2j is an epoxy or epoxy-based resin.

[0222] Advantageously, for all sealing layers, the polyamide P1i is the same.

[0223] Advantageously, the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA 1012, PA 1212, PA11, PA12, especially PA11 or PA12.

[0224] Advantageously, the polyamide P1i is a long-chain semi-aromatic polyamide, particularly PA 11 / 5T, PA 11 / 6T or PA 11 / 10T. Obviously, in this case, the ratio of 11 must be carefully selected so that the Tm of the polymer is below 280 °C, preferably 265 °C.

[0225] Advantageously, in the multi-layer structure, each reinforcing layer is composed of a composition including the same type of polymer P2j, particularly an epoxy resin or epoxy-based resin.

[0226] Advantageously, for all reinforcing layers, the polyamide P2j is the same.

[0227] Advantageously, in the multi-layer structure, each sealing layer is composed of a composition comprising the same type of polymer P1i, particularly a polyamide, and each reinforcing layer is composed of a composition comprising the same type of polymer P2j, particularly an epoxy or epoxy-based resin.

[0228] Advantageously, the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA 1012, PA 1212, PA11, PA12, especially PA 11 or PA12, and the polymer P2j is a semi-aromatic polyamide, particularly selected from: PAMPMDT / 6T, PA11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PAMPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA 11 / BACT / 10T, and PA 11 / MXDT / 10T.

[0229] In one embodiment, the multi-layer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA 1012, PA1212, PA11, PA12, especially PA11 or PA12, and the polymer P2j is a semi-aromatic polyamide, which is particularly selected from PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA11 / 6T / 10T a PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T.

[0230] In another embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA 1012, PA 1212, PA11, PA12, especially PA11 or PA12, and the polymer P2j is a semi-aromatic polyamide, which is particularly selected from PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T a PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T.

[0231] In yet another embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA 1012, PA 1212, PA11, PA12, or a semi-aromatic polyamide, which is particularly selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T, especially PA11 or PA12, and the polymer P2j is an epoxy or epoxy-based resin.

[0232] In another embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, particularly PA1010, PA1012, PA1212, PA12, or a semi-aromatic polyamide, which is particularly selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T, especially PA12, and the polymer P2j is an epoxy or epoxy-based resin.

[0233] Advantageously, the multilayer structure further comprises at least one outer layer consisting of a fibrous material made of continuous glass fibers impregnated with a transparent amorphous polymer, and the layer is the outermost layer of the multilayer structure.

[0234] The outer layer is a second reinforcing layer, but is transparent, which makes it possible to set text on the structure.

[0235] The outer layer never corresponds to the layer located above the outermost polyamide polymer composite reinforcing layer, as described above, the structure does not have it.

[0236] Regarding the fibrous material

[0237] Regarding the fibers that make up the fiber material, they are in particular mineral, organic or vegetable fibers.

[0238] Advantageously, the fiber material can be sized or unsized.

[0239] The fiber material can thus include up to 3.5% by weight of organic material (of the thermosetting or thermoplastic resin type), called sizing.

[0240] Mineral fibers include, for example, carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, or silicon carbide fibers. Organic fibers include, for example, fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aromatic polyamide fibers, or polyolefin fibers. Preferably, they are based on amorphous thermoplastic polymers and have a glass transition temperature Tg higher than that of the latter when the polymer or thermoplastic polymer mixture constituting the pre-impregnated matrix is amorphous, or a glass transition temperature Tg higher than the Tm of the latter when the polymer or thermoplastic polymer mixture constituting the pre-impregnated matrix is semi-crystalline. Advantageously, they are based on semi-crystalline thermoplastic polymers and have a melting temperature Tm higher than that of the latter when the polymer or thermoplastic polymer mixture constituting the pre-impregnated matrix is amorphous, or a melting temperature Tm higher than the Tm of the latter when the polymer or thermoplastic polymer mixture constituting the pre-impregnated matrix is semi-crystalline. Thus, there is no risk of melting of the organic fibers constituting the fiber material during the impregnation of the thermoplastic matrix of the final composite. Vegetable fibers include natural flax, hemp, lignin, bamboo, silk, especially spider silk, sisal, and other cellulose fibers, especially viscose. These vegetable fibers can be used pure, treated, or coated with a coating to promote the adhesion and impregnation of the thermoplastic polymer matrix.

[0241] The fiber material can also be a fabric woven or knitted from fibers.

[0242] It can also correspond to fibers with support threads.

[0243] These constituent fibers can be used individually or in a mixture. Thus, organic fibers can be mixed with mineral fibers to be pre-impregnated with thermoplastic polymer powder and to form a pre-impregnated fiber material.

[0244] Organic fiber bundles (strands) can have a certain grammage. They can further have a number of geometric shapes. The constituent fibers of the fiber material can further take the form of a mixture of these reinforcing fibers with different geometric shapes. The fibers are continuous fibers.

[0245] Preferably, the fiber material is selected from glass fibers, carbon fibers, basalt fibers or basalt-based fibers, or mixtures thereof, especially carbon fibers.

[0246] It is used in the form of one roving or several rovings.

[0247] According to another aspect, the present invention relates to a method for manufacturing a multilayer structure as defined above, characterized in that it comprises a step of preparing a sealing layer by means of extrusion blow molding, rotational molding, injection molding and / or extrusion.

[0248] In one embodiment, the method for manufacturing a multilayer structure comprises winding the reinforcing layer filaments as defined above around the sealing layer as defined above.

[0249] All the features detailed above also apply to the method. Description of the Drawings

[0250] Figure 1 Showing the Charpy (pendulum) notched impact at -40 °C of the following four liners according to ISO 179-1:2010: from left to right PA11, PA12, PA6 and PA66.

[0251] Figure 2 Showing the hydrogen gas permeability of liners PA12 and HDPE at 23 °C.

[0252] It is expressed in cc.mm / m 2 .24 h.atm. It can be expressed in 25 μ / m 2 .24 h.Pa.

[0253] Then the permeability must be multiplied by 101325.

[0254] Figure 3 Showing the Charpy notched impact at -40 °C of liners PA11 and PA12 according to ISO 179-1:2010: for the histograms of each group, PA11 is on the left and PA12 is on the right. The first group corresponds to 0% plasticizer, the second group corresponds to 7% plasticizer and the last group corresponds to up to 12% plasticizer. Examples

[0255] In all the examples, the tank is obtained by rotational molding the sealing layer (liner) at a temperature suitable for the properties of the thermoplastic resin used.

[0256] If the composite reinforcement is made of an epoxy resin or an epoxy-based resin, a wet filament winding process is used, which consists of winding the fibers around the liner, which have previously been pre-impregnated in a bath of liquid epoxy or a bath of epoxy-based liquid. Then the storage tank is polymerized in an oven for 2 hours.

[0257] In all other cases, a fiber material impregnated with a thermoplastic resin (tape) is used before use. The tape is deposited by filament winding at a speed of 12 m / min using an automatic operating device with a 1500 W laser heater and there is no polymerization step.

[0258] Example 1: Charpy notched impact at -40 °C according to ISO 179-1:2010

[0259] Two long-chain liners and two short-chain liners of PA11 and PA12 are prepared by rotational molding as described above.

[0260] The Charpy notched impact test is carried out on these four liners at -40 °C and the results are shown in Figure 1 .

[0261] The cold resistance of the long-chain liners is significantly better than that of the short-chain PA6 and PA66 liners.

[0262] Example 2:

[0263] The permeabilities of PA11 and PA12 (Arkema) and HDPE ( HMN TR-942 (Chevron Phillips)) liners

[0264] Two long-chain liners are prepared by rotational molding: one with PA11 (Arkema) and the second with PA12 (Arkema), and an HDPE liner is prepared by rotational molding, and the hydrogen permeability at 23 °C is tested.

[0265] This consists of purging the upper surface of the membrane with a test gas (hydrogen), and measuring the flow rate diffusing through the membrane in the lower part purged with the carrier gas nitrogen by gas chromatography.

[0266] The experimental conditions are shown in Table 1:

[0267] [Table 1]

[0268]

[0269] The results are shown in Figure 2 and show that both the PA11 liner and the PA12 liner have much lower permeabilities than the HDPE liner.

[0270] Example 3: Influence of the proportion of plasticizer (N-butylbenzenesulfonamide: BBSA) on the Charpy notched impact at -40 °C according to ISO 179-1:2010

[0271] Two liners of PA11 and PA12 are prepared by rotational molding without a plasticizer or including 7 or 12% of the plasticizer (BBSA) relative to the total weight of the composition.

[0272] These linings were subjected to Charpy notched impact tests at -40 °C according to ISO 179-1:2010 and the results are shown in Figure 3 .

[0273] Plasticizers have an adverse effect at low temperatures, weakening the structure and increasing the permeability, in particular increasing the permeability by 50% in the case of 7% BBSA.

[0274] Example 4

[0275] The effect of the proportion of an impact modifier ("LT cocktail" with the following composition: 4700 (50%) + AX8900 (25%) + 3110 (25%)) on the hydrogen permeability of the PA12 lining.

[0276] The hydrogen permeability of PA12 linings without plasticizer and with or without impact modifier was tested and reported in Table 2.

[0277] [Table 2]

[0278] lining <![CDATA[Permeability (cc·25μm 2 .24 h·atm)]]> only PA12 7,300 PA12 + 18% impact modifier 15,000 PA12 + 30% impact modifier 22,000

[0279] The permeability can also be expressed in (cc·25μm 2 ·24h·Pa).

[0280] Then the permeability must be multiplied by 101325.

[0281] The results show that the proportion of the impact modifier affects the hydrogen permeability.

[0282] The greater the proportion of the impact modifier, the greater the permeability.

[0283] Example 5

[0284] A type-IV hydrogen storage tank composed of a T700SC31E (produced by Toray) carbon fiber epoxy composite reinforcement (Tg 120 °C) and a PA11 sealing layer.

[0285] The operating temperature is sufficient to fill the tank quickly, especially within 3 to 5 minutes.

[0286] Example 6 (counterexample):

[0287] A type-IV hydrogen storage tank composed of a T700SC31E (produced by Toray) carbon fiber epoxy composite reinforcement (Tg 120 °C) and an HDPE sealing layer.

[0288] The operating temperature is too low to fill the tank quickly, especially within 3 to 5 minutes.

[0289] Example 7: A type-IV hydrogen storage tank composed of a T700SC31E (produced by Toray) carbon fiber epoxy composite reinforcement BACT / 10T and a PA12 sealing layer.

[0290] The selected BACT / 10T composition has a melting temperature Tm of 283 °C, a crystallization temperature Tc of 250 °C, and a glass transition temperature of 164 °C.

[0291] The Tg, Tc, and Tm were measured by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0292] The BACT / 10T PA-based composite has a matrix with a high Tg but no long cross-linking of the 8-hour type at 140 °C.

[0293] Therefore, after removing the fibers, the tank is completed, saving 8 hours of process time.

Claims

1. A multi-layer structure intended for the transport, distribution, or storage of hydrogen, comprising from the inside out at least one sealing layer (1) and at least one composite reinforcement layer (2), wherein the innermost composite reinforcement layer is wound around the outermost adjacent sealing layer (1), wherein the sealing layer consists of a sealing layer composition, the sealing layer composition comprising: At least one semi-crystalline long-chain polyamide thermoplastic polymer P1i, which is more than 50% by weight relative to the total weight of the sealing layer composition, and which comprises a Tm measured according to ISO 11357-3:2013 greater than 160 °C, where i = 1 to n and n is the number of sealing layers, The long-chain polyamide thermoplastic polymer has an average number of carbon atoms per nitrogen atom greater than 9, Excluding polyether block amides (PEBA), An impact modifier up to 50% by weight relative to the total weight of the sealing layer composition, A plasticizer up to 1.5% by weight relative to the total weight of the sealing layer composition, The sealing layer composition has no nucleating agent, The at least one major polyamide thermoplastic polymer in each sealing layer is the same or different, And at least one of the composite reinforcing layers consists of a fibrous material in the form of continuous fibers impregnated with a composite reinforcing layer composition, the composite reinforcing layer composition comprising at least one polymer P2j which is more than 50% by weight relative to the total weight of the composite reinforcing layer composition, where j = 1 to m and m is the number of composite reinforcing layers, The structure has no polyamide polymer layer which is the outermost and adjacent to the outermost composite reinforcing layer, Where PA6 and PA610 are excluded from the sealing layer composition, Where the polymer P2j is an epoxy resin or an epoxy-based resin.

2. The multi-layer structure according to claim 1, characterized in that the Tm is greater than 170 °C.

3. The multi-layer structure according to claim 1, characterized in that the sealing layer consists of a sealing layer composition, the sealing layer composition comprising: Up to less than 15% by weight of an impact modifier.

4. The multi-layer structure according to claim 3, characterized in that the sealing layer consists of a sealing layer composition, the sealing layer composition comprising: Up to less than 12% by weight of an impact modifier.

5. The multi-layer structure according to claim 1, characterized in that at least one of the composite reinforcement layers consists of a fibrous material in the form of continuous fibers impregnated with a composite reinforcement layer composition, the composite reinforcement layer composition comprising more than 50% by weight of an epoxy resin or an epoxy-based resin.

6. The multi-layer structure according to claim 1, characterized in that each sealing layer comprises the same type of polyamide.

7. The multi-layer structure according to any one of claims 1 to 2, characterized in that each composite reinforcement layer comprises the same type of polymer.

8. The multi-layer structure according to claim 7, characterized in that each composite reinforcement layer comprises an epoxy resin or an epoxy-based resin.

9. The multi-layer structure according to claim 7, characterized in that each sealing layer comprises the same type of polymer and each composite reinforcement layer comprises the same type of polymer.

10. The multi-layer structure according to claim 9, characterized in that each sealing layer comprises an epoxy resin or an epoxy-based resin.

11. The multi-layer structure according to claim 9, characterized in that each composite reinforcing layer comprises an epoxy resin or an epoxy-based resin.

12. The multi-layer structure according to any one of claims 1 to 6, characterized in that it has a single sealing layer and a single composite reinforcing layer.

13. The multi-layer structure according to claim 1, characterized in that the polymer P1i is: a long-chain aliphatic polyamide; or a semi-aromatic polyamide.

14. The multi-layer structure according to claim 13, characterized in that the polymer P1i is a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11, PA12.

15. The multi-layer structure according to claim 14, characterized in that the polymer P1i is a long-chain aliphatic polyamide selected from PA 11 or PA12.

16. The multi-layer structure according to claim 13, characterized in that the polymer P1i is a semi-aromatic polyamide selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

17. The multi-layer structure according to claim 1 or 13, characterized in that the multi-layer structure is composed of a single composite reinforcing layer and a single sealing layer, wherein the polymer P1i is: a long-chain aliphatic polyamide; or a semi-aromatic polyamide, and the polymer P2j is an epoxy or an epoxy-based resin.

18. The multi-layer structure according to claim 17, characterized in that the polymer P1i is a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11, PA12.

19. The multi-layer structure according to claim 17, characterized in that the polymer P1i is a semi-aromatic polyamide selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

20. The multi-layer structure according to claim 17, characterized in that the polymer P1i is selected from PA11 or PA12.

21. The multi-layer structure according to claim 1, characterized in that the fiber material of the composite reinforcing layer is selected from glass fiber, carbon fiber, basalt fiber or basalt-based fiber, or a mixture thereof.

22. The multi-layer structure according to claim 21, characterized in that the fiber material of the composite reinforcing layer is selected from carbon fiber.

23. The multi-layer structure according to any one of claims 1 to 6, characterized in that the structure further comprises at least one outer layer composed of a fibrous material made of continuous glass fibers impregnated with a transparent amorphous polymer, and the outer layer is the outermost layer of the multi-layer structure.

24. The method for manufacturing a multi-layer structure as defined in any one of claims 1 to 23, characterized in that it comprises the step of preparing a sealing layer by extrusion blow molding, rotational molding, injection molding and / or extrusion.

25. The method for manufacturing a multi-layer structure as defined in claim 24, characterized in that it comprises the step of filament winding a composite reinforcing layer as defined in any one of claims 1 to 5 around a sealing layer as defined in any one of claims 1 to 5.

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